The laparoscopic sleeve gastrectomy (LSG) is also known as vertical sleeve gastrectomy (VSG) and gastric sleeve. This surgery is a permanent irreversible operation performed via keyhole surgery where a portion of the stomach is removed.
Normally the stomach is an expansible muscular bag (imagine it like a balloon in that it can expand and deflate) which can have the capacity of 2L. Following the sleeve gastrectomy procedure the capacity of the stomach is reduced to approximately 200-250mL.
To perform this surgery, I divide the stomach with surgical staples along its entire length and the larger portion of stomach which has been divided is removed. The remaining stomach is long and narrow and roughly the shape of a banana and is approximately 1/10 the size of the original stomach. This narrower stomach is often referred to as a pouch or sleeve because of its shape and smaller size.